Many air conditioning and refrigeration units employ an evaporator coil to dehumidify and cool ambient air in a building. Typically, the evaporator coil is located inside the housing of the furnace of the air conditioning unit, and is made up of refrigerant piping loops. The evaporator coil is colder than the air being conditioned, so it condenses water liquid continuously while in operation. A condensate drain pan is typically installed below the evaporator coil, such that when the furnace fan blows air across and through the evaporator coil, the refrigerant piping loops will cool the air. During this process, water vapor in the air will condense to liquid and collect on the evaporator coil. The water (or condensate) will therefore drip from the evaporator coils into the drain pan below. The drain pan has one or more outlet ports, and a drainpipe is attached to these outlet ports for outflow of the condensate from the drain pan to a location outside of the housing.
Ideally, the condensate will drain through the drain pan outlets and through the drainpipe away from the drain pan. However, the drainpipe can often become occluded by algae, mold, mildew, dirt, or other debris, which can result in the blockage of the drainpipe. This blockage in the drainpipe prevents the condensate liquid from emptying from the drain pan, which further results in drain pan overflows. Typical drain pans are only about an inch deep, so it does not take long for the water to overflow from the drain pan when the drainpipe is clogged. Such overflows from the drain pan can cause water damage in the surrounding areas. Consequently, it is important for the owner to know about any potential drainpipe obstructions at the earliest possible time.